Protease Inhibitor Resistance in the First 3 Years of Second-Line Antiretroviral Therapy for HIV-1 in Sub-Saharan Africa by Boender, T, Hamers, R, Ondoa, P, Wellington, M, Chimbetete, C, Siwale, M, Labib Maksimos, E, Balinda, S, Kityo, C, Adeyemo, T, Akanmu, A, Mandaliya, K, Botes, M, Stevens, W, Rinke de Wit, T, Sigaloff, K